The surface of beta-Ga2O3 (1 0 0) single crystal grown with floating zone method was treated by chemical mechanical-polishing (CMP) for 30-120 min followed by annealing in oxygen atmosphere at temperature 600-1100 degrees C for 3-6 h. The evolution of the step arrangement was investigated with reflection high energy electron diffraction and atomic force microscopy. Atomically smooth surfaces with atomic step and terrace structure of beta-Ga2O3 substrates were successfully obtained after just CMP treatment as well as CMP treatment and post annealing at 1100 degrees C for 3 h. The uniform step height was 0.57 nm, and smooth terrace width was 100 nm, where the misorientation angle was about 0.36 degrees. The obtained atomically smooth surface provides a potential application for the high-quality epitaxial film growth. (C) 2008 Elsevier B. V. All rights reserved.